JP5230849B2 - Hydrogen generator, fuel cell system, and operation method thereof - Google Patents

Abstract

A hydrogen generation apparatus (100) includes: a reformer (1) configured to generate a hydrogen-containing gas by causing a reforming reaction of a raw material; a combustor (2) configured to heat the reformer; and a controller (5) configured to set a controlled temperature of the reformer to a first temperature when an oxygen concentration in the raw material is in a first state where the oxygen concentration is relatively low, and change the controlled temperature of the reformer to a second temperature higher than the first temperature when the oxygen concentration in the raw material is in a second state where the oxygen concentration is relatively higher than the oxygen concentration in the first state.

Description

  The present invention relates to a hydrogen generator, a fuel cell system, and an operation method thereof. More specifically, the present invention relates to a hydrogen generator that generates a hydrogen-containing gas using raw materials, a fuel cell system including the hydrogen generator, and an operation method thereof.

The fuel cell system supplies a hydrogen-containing gas (a gas containing H ₂ gas) and an oxygen-containing gas to a fuel cell stack (hereinafter simply referred to as “fuel cell”), and performs an electrochemical reaction between hydrogen and oxygen. It is a system that generates electricity by advancing and extracting chemical energy as electrical energy. The fuel cell system not only has high power generation efficiency, but also can easily use thermal energy generated during power generation. For this reason, the fuel cell system is being developed as a distributed power generation system capable of realizing high energy utilization efficiency.

  In general, there are often no facilities for supplying hydrogen-containing gas. For this reason, hydrogen generators are provided in conventional fuel cell systems. A typical hydrogen generator generates a hydrogen-containing gas (reformed gas) using, as a raw material, city gas mainly composed of natural gas, LPG, or the like supplied from an existing infrastructure. For this purpose, the hydrogen generator is, for example, modified to generate a hydrogen-containing gas by performing a reforming reaction with steam at a temperature of 600 to 700 ° C. using a desulfurization section that removes sulfur components in the raw material, a Ru catalyst, or a Ni catalyst. A quality device is provided (for example, see Patent Document 1).

  The hydrogen-containing gas obtained by the reforming reaction usually contains carbon monoxide derived from the raw material. When the concentration of carbon monoxide is high, the power generation characteristics of the fuel cell are degraded. Therefore, the hydrogen generator is often provided with a reactor such as a shifter, a selective oxidizer, and a methanation remover in addition to the reformer. The shifter includes a Cu—Zn-based catalyst, and reduces the carbon monoxide by causing a shift reaction between carbon monoxide and water vapor at a temperature of 200 ° C. to 350 ° C. The selective oxidizer selectively oxidizes carbon monoxide at a temperature of 100 ° C. to 200 ° C. to further reduce the carbon monoxide. The methanation remover selectively reduces carbon monoxide by selectively methanating it. A selective oxidizer or a methanation remover is also called a selective remover.

  Now, oxygen may be temporarily mixed in the raw material due to the structure of the infrastructure. Thus, a preliminary reforming method for oxygen-containing process gas (for example, natural gas, peak shaving gas, LPG, etc.) has been proposed (for example, see Patent Document 2).

JP 2003-183005 A Japanese Patent Laid-Open No. 2001-80907

  Here, as described in Patent Document 2, when the oxygen concentration in the raw material is relatively high, the reformer overheats due to heat generated by the oxidation reaction between hydrogen and oxygen in the hydrogen-containing gas. It may be determined that the operation may be stopped.

  The present invention solves such a problem, and in a state where the oxygen concentration in the raw material is high, the hydrogen generator and the fuel cell that can reduce the possibility that the reformer is determined to be overheated and shut down than before It is an object to provide a system and a method for operating the system.

  In order to solve the above problems, a hydrogen generator of the present invention includes a reformer that reforms a raw material to generate a hydrogen-containing gas, a combustor that heats the reformer, and an oxygen concentration in the raw material. Is the second state where the control temperature of the reformer is the first temperature and the oxygen concentration in the raw material is relatively higher than the first state. And a controller that changes the control temperature of the reformer to a second temperature higher than the first temperature.

  The general and specific configurations described above can also be implemented as a fuel cell system, a method for operating a hydrogen generator, and the like.

  According to the hydrogen generator, the fuel cell system, and the operation method thereof according to the present invention, it is possible to reduce the possibility that the reformer is determined to be overheated and shut down when the oxygen concentration in the raw material is high. .

FIG. 1 is a block diagram illustrating an example of a schematic configuration of a hydrogen generator according to the first embodiment. FIG. 2 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the first embodiment. FIG. 4 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the first modification of the first embodiment. FIG. 4 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the second modification of the first embodiment. FIG. 5 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the second embodiment. FIG. 6 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the first modification of the second embodiment. FIG. 7 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the second modification of the second embodiment. FIG. 8 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the third modification of the second embodiment. FIG. 9 is a block diagram illustrating an example of a schematic configuration of a fuel cell system according to the third embodiment.

(First embodiment)
The hydrogen generator according to the first embodiment includes a reformer that generates a hydrogen-containing gas by reforming a raw material, a combustor that heats the reformer, and a first oxygen concentration in the raw material that is relatively low. The control temperature of the reformer is set to the first temperature when the state is 1, and the control of the reformer is performed when the oxygen concentration in the raw material is the second state that is relatively higher than the first state. A controller for changing the temperature to a second temperature higher than the first temperature.

  The operation method of the hydrogen generator according to the first embodiment includes a step of reforming a raw material in a reformer to generate a hydrogen-containing gas, a step of heating the reformer by a combustor, and oxygen in the raw material A step of setting the control temperature of the reformer as the first temperature when the concentration is in a relatively low first state; and a second state in which the oxygen concentration in the raw material is relatively higher than in the first state The control temperature of the reformer is changed to a second temperature higher than the first temperature.

  With such a configuration, it is possible to reduce the possibility that the reformer is determined to be overheated and shut down in a state where the oxygen concentration in the raw material is high, compared to the conventional case.

  In the hydrogen generator, the controller may stop the operation after changing the control temperature of the reformer to the second temperature and when the temperature of the reformer cannot be controlled to the second temperature.

  “The case where the temperature of the reformer cannot be controlled to the second temperature” means, for example, a case where the temperature of the reformer is equal to or higher than the second upper limit temperature higher than the second temperature.

  “Stopping the operation” means stopping the hydrogen generation operation in the reformer. Also, the stop of the hydrogen generation operation means that at least one of the operations necessary for the progress of the reforming reaction is stopped in the reformer. For example, it means stopping at least one of the supply of reaction raw materials to the reformer and the heating operation of the reformer. In the case of the steam reforming reaction, the reaction raw materials are the raw material and water vapor. In the case of the autothermal reaction, the reaction raw material is the raw material, water vapor and air. In the case of the partial oxidation reaction, the reaction raw material is the raw material and air. .

  In the above hydrogen generator, the controller may stop the operation when the oxygen concentration in the raw material is the third state having a relatively high oxygen concentration in the second state.

[Device configuration]
FIG. 1 is a block diagram showing an example of a schematic configuration of the fuel cell system according to the first embodiment.

  In the example shown in FIG. 1, the hydrogen generator 100 of this embodiment includes a reformer 1, a combustor 2, a temperature detector 3, and a controller 5.

  Hereinafter, a configuration example of each component included in the example illustrated in FIG. 1 will be described.

  The reformer 1 causes a reforming reaction of the raw material to generate a hydrogen-containing gas. The raw material contains at least an organic compound having carbon and hydrogen as constituent elements, and specific examples include natural gas, city gas, hydrocarbons such as LPG and LNG, and alcohols such as methanol and ethanol. City gas refers to gas supplied from a gas company to households through piping. The reforming reaction may be any reforming reaction, and specific examples include a steam reforming reaction, an autothermal reaction, and a partial oxidation reaction.

  The hydrogen-containing gas generated in the reformer 1 is supplied to the hydrogen utilization device via the hydrogen supply path 11.

  The combustor 2 heats the reformer 1. At least the above raw materials are used as the fuel for the combustor 2, and when the generation of the hydrogen-containing gas is started in the reformer 1, the hydrogen-containing gas is also used as the fuel.

  The hydrogen generator 100 includes an oxygen concentration state detector that detects the state of the oxygen concentration contained in the raw material. The oxygen concentration state detector may be any detector as long as it can detect the state of the oxygen concentration contained in the raw material. Here, the state of oxygen concentration is defined as meaning at least one of an oxygen concentration value in the raw material and a relative high or low state of the oxygen concentration in the raw material.

  Specifically, the oxygen concentration state detector is at least one of a detector that directly detects the state of the oxygen concentration contained in the raw material and a detector that indirectly detects the state of the oxygen concentration contained in the raw material. Is used. As a detector that directly detects the state of oxygen concentration contained in the raw material, an oxygen concentration detector provided in the raw material flow path, information acquisition that acquires oxygen concentration information from an external information holding body that holds oxygen concentration information An example is a container. Examples of the information holder include a user, a server that holds oxygen concentration information, a distributor that holds oxygen concentration information, and a gas company. The method by which the information acquisition unit acquires the oxygen concentration information from the information holding body is arbitrary. For example, the information acquisition device may acquire oxygen concentration information via wired communication, wireless communication, or the like, or the user may acquire oxygen concentration information by manually inputting the information directly into the information acquisition device.

  The detector that indirectly detects the state of the oxygen concentration contained in the raw material is a detector that detects a physical quantity that correlates with the state of the oxygen concentration in the raw material. As a detector for indirectly detecting the state of oxygen concentration contained in the raw material, a first detector for detecting the temperature of the hydrodesulfurizer, a second detector for detecting the temperature of the reformer, and supply of the raw material Pressure detector that detects pressure, oxygen concentration detector that detects oxygen concentration in raw materials, ammonia concentration detector that detects ammonia concentration in hydrogen-containing gas, temperature detector that detects outside air temperature, oxygen concentration state An information acquisition unit for acquiring correlated raw material composition information is exemplified. Examples of the raw material composition information correlated with the oxygen concentration state include information indicating that peak shaving is being performed.

  The oxygen concentration state detector is communicably connected to the controller 5 and sends information related to the oxygen concentration state to the controller 5. Examples of the information on the oxygen concentration state include a hydrodesulfurizer temperature, a reformer temperature, and an oxygen concentration.

  As described above, the first detector detects, as the temperature of the hydrodesulfurizer, the magnitude of heat generated when the oxygen in the raw material and the hydrogen in the hydrogen-containing gas supplied to the hydrodesulfurizer undergo an oxidation reaction. . The controller 5 can determine the relative high / low state of the oxygen concentration based on the value acquired from the first detector.

  The detector that directly detects the temperature of the hydrodesulfurizer may be provided at any location as long as the temperature of the hydrodesulfurizer can be detected. Specifically, a detector that detects the temperature of the outer shell of the hydrodesulfurizer, the gas temperature in the hydrodesulfurizer, the gas temperature that has passed through the hydrodesulfurizer, the catalyst temperature in the hydrodesulfurizer, etc. Is done.

  The detector that indirectly detects the temperature of the hydrodesulfurizer is a detector that detects a physical quantity correlated with the temperature of the hydrodesulfurizer. Detectors that indirectly detect the temperature of the hydrodesulfurizer include detectors that detect the concentration of sulfur compounds in the raw material that has passed through the hydrodesulfurizer, and the concentration of carbon monoxide in the raw material that has passed through the hydrodesulfurizer. The detector etc. which detect this are illustrated.

  When the temperature of the hydrodesulfurizer rises, depending on the type of hydrodesulfurization catalyst (for example, CoMo hydrodesulfurization catalyst), the methanation reaction of carbon monoxide proceeds and hydrogen is consumed in the methanation reaction. . Then, the hydrogenation reaction amount of the sulfur compound decreases, and the concentration of the sulfur compound contained in the raw material passing through the hydrodesulfurizer increases. The detector that detects the sulfur compound concentration in the raw material that has passed through the hydrodesulfurizer can detect the increase in the temperature of the hydrodesulfurizer indirectly by detecting the increase in the sulfur compound concentration in the raw material. become.

  Further, when the temperature of the hydrodesulfurizer rises, depending on the type of hydrodesulfurization catalyst (for example, a CuZn-based hydrodesulfurization catalyst), a reverse shift reaction proceeds and the concentration of carbon monoxide increases. Therefore, the detector that detects the concentration of carbon monoxide in the raw material that has passed through the hydrodesulfurizer indirectly detects the increase in the temperature of the hydrodesulfurizer by detecting the increase in the concentration of carbon monoxide. Is possible.

  The second detector detects the magnitude of heat generated when the oxygen in the raw material supplied to the reformer and the hydrogen generated in the reformer undergo an oxidation reaction as the temperature of the reformer. The controller 5 can determine the relative high / low state of the oxygen concentration based on the value acquired from the second detector.

  The second detector may be any detector as long as it can detect the temperature of the reformer. Specifically, at least one of a detector that directly detects the temperature of the reformer and a detector that indirectly detects the temperature of the reformer is used as the second detector.

  The detector that directly detects the temperature of the reformer may be provided at any location as long as the temperature of the reformer can be detected. Specifically, a detector that detects the temperature of the outer shell of the reformer, the temperature of the reforming catalyst, the gas temperature in the reformer, the gas temperature that has passed through the reformer, and the like is exemplified.

  The detector that indirectly detects the temperature of the reformer is a detector that detects a physical quantity correlated with the temperature of the reformer. As a detector that indirectly detects the temperature of the reformer, a hydrogen concentration detector that detects the hydrogen concentration in the hydrogen-containing gas that has passed through the reformer, a device that receives heat transfer from the reformer (for example, Examples thereof include a temperature detector that detects the temperature of the hydrodesulfurizer, a temperature detector that detects the temperature of a device (for example, a transformer) through which the hydrogen-containing gas that has passed through the reformer flows.

  Usually, the raw material supply pressure is lower than the normal value before the peak shaving is performed. Here, the raw material supply pressure returns to the normal value by executing the peak shaving. When the pressure in the raw material supply path 10 detected by the pressure detector returns from the value lower than the normal value to the normal value, the controller 5 performs peak shaving and the oxygen concentration in the raw material is high. Can be determined.

  Also, when the outside air temperature is low and the heat demand is high, peak shaving occurs to make up for the insufficient raw material. Therefore, for example, when the detected value of the temperature detector that detects the outside air temperature is equal to or less than a value (for example, −5 ° C.) that is estimated to cause peak shaving, the oxygen concentration in the raw material is high due to peak shaving. It may be determined that In addition, when the decrease (temperature decrease) in the detection value of the temperature detector that detects the outside air temperature is equal to or greater than the value estimated to cause peak shaving (for example, 10 ° C.), oxygen in the raw material by peak shaving It may be determined that the concentration is high.

  The oxygen concentration detector can detect the oxygen concentration value itself.

  The ammonia concentration detector detects the ammonia concentration in the hydrogen-containing gas. When oxygen is mixed into the raw material, air is usually mixed into the raw material, so that not only oxygen but also nitrogen is mixed into the raw material. Nitrogen mixed in the raw material reacts with hydrogen generated in the reformer 1 to generate ammonia. Therefore, based on the concentration acquired from the ammonia concentration detector, it is possible to determine the relative level of the oxygen concentration.

  The temperature detector 3 shown in FIG. 1 is a temperature detector for detecting the state of oxygen concentration in the raw material supplied to the reformer 1, and is an example of an oxygen concentration state detector. The temperature detector 3 is disposed at a predetermined position of the reformer 1 that can detect the temperature according to the state of the oxygen concentration in the raw material. In other words, the temperature detector 3 is an example of a second detector. The temperature detector 3 is disposed, for example, in the upstream portion of the reformer 1. This is because oxygen in the raw material that has flowed into the reformer 1 is mostly consumed in the upstream portion of the reformer 1 due to an oxidation reaction with hydrogen, so the state of oxygen concentration in the raw material This is because the temperature of the reformer 1 is likely to change according to the above.

  The controller 5 only needs to have a control function, and includes an arithmetic processing unit (not shown) and a storage unit (not shown) that stores a control program. Examples of the arithmetic processing unit include an MPU and a CPU. A memory is exemplified as the storage unit. The controller may be composed of a single controller that performs centralized control, or may be composed of a plurality of controllers that perform distributed control in cooperation with each other. This also applies to the controllers of other embodiments and modifications thereof. In the example of FIG. 1, the controller 5 is communicably connected to the temperature detector 3 and controls the combustion amount of the combustor 2 based on the temperature detected by the temperature detector 3.

  Control of the combustion amount of the combustor 2 is executed by controlling the flow rate of fuel to the combustor 2. Specifically, for example, the combustor 2 is configured to burn using the hydrogen-containing gas generated in the reformer 1, and by controlling the flow rate of the raw material to the reformer 1, The amount of combustion is controlled. The control of the combustion amount of the combustor 2 is not limited to this example. For example, the hydrogen generator 100 includes a flow path that bypasses the reformer 1 and supplies the raw material directly to the combustor 2, and controls the flow rate of the raw material that is supplied through the flow path, thereby The combustion amount of the vessel 2 may be controlled.

  Alternatively, the combustion amount of the combustor 2 may be controlled by controlling both the flow rate of the raw material supplied to the reformer 1 and the flow rate of the raw material supplied directly to the combustor 2. That is, the hydrogen generator 100 controls the amount of combustion in the combustor 2 by controlling at least one of the flow rate of the raw material supplied to the reformer 1 and the flow rate of the raw material supplied directly to the combustor 2.

  The hydrogen generator 100 further includes a raw material supplier that is not shown.

  The raw material supplier adjusts the flow rate of the raw material supplied to the reformer 1. The raw material supplier may have any configuration as long as the flow rate of the raw material can be adjusted, and is configured by, for example, at least one of a booster and a flow rate adjustment valve. The raw material supplier supplies the raw material to the reformer 1 via an adsorptive desulfurizer, for example.

  The hydrogen generator 100 further includes a water vapor supply device (not shown). The steam supplier supplies steam to the reformer 1. The water vapor supply device includes an evaporator (not shown) and a water supply device (not shown). In addition, when the reforming reaction in the reformer 1 is a partial oxidation reaction, the steam supply unit may not be provided.

  Although not shown in FIG. 1, the hydrogen generator 100 may include a carbon monoxide reducer downstream of the reformer 1. The carbon monoxide reducer reduces the concentration of carbon monoxide in the hydrogen-containing gas produced by the reformer 1. As the carbon monoxide reducer, at least one of a transformer and a carbon monoxide remover is used. The transformer reduces carbon monoxide by a shift reaction. The carbon monoxide remover reduces carbon monoxide in at least one of an oxidation reaction and a methanation reaction.

  In the hydrogen generator of the present embodiment, when the oxygen concentration in the raw material is in the first state that is relatively low, the control temperature of the reformer is set to the first temperature, and the oxygen concentration in the raw material is the first concentration. When the second state is higher than the state, the control temperature of the reformer is changed to a second temperature higher than the first temperature.

  FIG. 2 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the first embodiment. Hereinafter, an example of the operation of the hydrogen generator 100 will be described with reference to FIG. The operation is executed under the control of the controller 5. This also applies to other modified examples and embodiments.

  When the hydrogen generator 100 starts the determination operation of the oxygen concentration state (start), the controller 5 determines whether or not the oxygen concentration state is the second state based on the information received from the temperature detector 3. Determination is made (step S101). Here, the first state is when the oxygen concentration in the raw material is in a relatively low state. The second state refers to a state in which the oxygen concentration in the raw material is relatively higher than in the first state. The first state and the second state are appropriately set according to the design of the reformer. For example, the first state is set as a state in which the oxygen concentration in the raw material is in the range of 0 ppm to 1000 ppm. The second state is set as a state where the oxygen concentration in the raw material is greater than 1000 ppm.

  The determination can be made, for example, based on whether or not the temperature detected by the temperature detector 3 is equal to or higher than a predetermined first upper limit temperature. In this case, when the detected temperature is equal to or higher than the first upper limit temperature, it is determined that the second state is established. When the detected temperature is lower than the first upper limit temperature, the second state is not established, that is, the first state is established. It is determined. The first upper limit temperature is defined as the temperature when the oxygen concentration in the raw material is in the second state, and a value smaller than the heat resistant temperature of the reformer 1 is set. For example, the first upper limit temperature can be 700 ° C.

  When the state of the oxygen concentration in the raw material is the first state, the determination result in step S101 is No, and the controller 5 maintains the control temperature of the reformer at the first temperature and the hydrogen generator 100 is maintained. Is continued (step S102), and the determination operation is ended (END).

  When the state of the oxygen concentration in the raw material is the second state, the determination result in step S101 is Yes, and the controller 5 changes the control temperature of the reformer to the second temperature higher than the first temperature. (Step S103), the determination operation ends (END). Thereby, the combustion amount of the combustor 2 is controlled by the controller 5 so that the temperature detected by the temperature detector 3 becomes the second temperature. Note that both the first temperature and the second temperature are set to a temperature lower than the heat resistant temperature of the reformer 1, for example, the first temperature is set to 670 ° C. and the second temperature is set to 730 ° C.

  With this operation, the possibility that the reformer is determined to be overheated and shut down in a state where the oxygen concentration in the raw material is high can be reduced as compared with the conventional case.

  The method for determining whether or not the oxygen concentration in the raw material is in the second state that is higher than the first state (step S101 in FIG. 3) is any if the state of the oxygen concentration in the raw material can be determined. It may be a simple method. For example, an oxygen concentration state detector that detects the state of oxygen concentration in the raw material may be provided, and determination may be made using the detection value of this detector. In the above example, the temperature detector 3 corresponds to an oxygen concentration state detector, and based on a comparison between the temperature detected by the temperature detector 3 and a predetermined threshold temperature, the level of oxygen concentration in the raw material is determined. Yes.

  As a method for determining the state of the oxygen concentration using the temperature detected by the temperature detector 3, whether or not the rising speed per unit time of the temperature detected by the temperature detector 3 is equal to or higher than a predetermined first rising speed. The determination may be made by the following. In this case, when the rising speed is equal to or higher than the first upper limit speed, it is determined to be in the second state, and when it is lower than the first upper limit speed, it is not in the second state, that is, in the first state. It is determined. As a unit of the rising speed, for example, ° C./min can be used. The first upper limit speed is appropriately set according to the design of the reformer 1, and may be, for example, 50 ° C./min. The increase in temperature may occur later than the increase in oxygen concentration. By the determination using the temperature increase rate, the oxygen concentration increase can be detected more quickly than the determination using the temperature itself. When the determination is performed using the temperature increase rate, the controller 5 may further include a timer (not shown). The controller 5 receives the temperature detected by the temperature detector 3 every predetermined time, stores it in the storage unit, and calculates the rate of temperature increase per unit time.

  Although the method for determining the oxygen concentration state in the raw material when the temperature detector 3 is used as the oxygen concentration state detector has been described above, the method using other oxygen concentration state detectors can be similarly executed. .

  Specifically, when the first detector that detects the temperature of the hydrodesulfurizer is used as the oxygen concentration state detector, whether the detection value of the first detector is equal to or higher than a first threshold (eg, 320 ° C.). The state of the oxygen concentration in the raw material may be determined based on whether or not. Or you may determine the state of the oxygen concentration in a raw material based on whether the change speed of the detected value of a 1st detector is more than a 1st speed threshold value (for example, 30 degree-C / min).

  When an oxygen concentration detector is used as the oxygen concentration state detector, the state of the oxygen concentration in the raw material is determined based on whether or not the detected concentration of the oxygen concentration detector is equal to or higher than the first upper limit oxygen concentration (for example, 1000 ppm). You may judge.

  When an ammonia concentration detector is used as the oxygen concentration state detector, the state of oxygen concentration in the raw material is determined based on whether or not the detected concentration of the ammonia concentration detector is equal to or higher than the first upper limit ammonia concentration (for example, 8000 ppm). May be.

  When a pressure detector is used as the oxygen concentration state detector, oxygen in the raw material is determined based on whether the detected pressure of the pressure detector is equal to or lower than a first upper limit pressure value (for example, +0.5 kPa with respect to atmospheric pressure). The density state may be determined.

[First Modification]
In the hydrogen generator of the present modification, the controller 5 generates hydrogen in the reformer when the temperature of the reformer 1 cannot be controlled to the second temperature after changing the control temperature of the reformer 1 to the second temperature. Stop operation.

  With such a configuration, it is possible to reduce reformer malfunctions such as reformer failure or reformer degradation.

  The hydrogen generator of this modification may be configured in the same manner as in the first embodiment except for the above features.

  Next, the hydrogen generator of this modification will be described in detail.

  The hardware configuration of the hydrogen generator of this modification can be the same as that shown in FIG. Therefore, the same name and code | symbol are attached | subjected about the component which is common in the fuel cell system of this modification, and the hydrogen generator 100 of 1st Embodiment, and detailed description is abbreviate | omitted.

  FIG. 3 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the first modification of the first embodiment.

  Hereinafter, the operation method of the hydrogen generator according to the first modification of the present embodiment will be described with reference to FIG.

  Since the operations in steps 201 to 203 are the same as those in steps S101 to S103 in FIG.

  In this modification, after step S203, it is determined whether or not the temperature of the reformer can be maintained at the second temperature, that is, whether or not the reformer can be controlled at the second temperature (step S204). The determination as to whether or not the temperature of the reformer can be maintained at the second temperature is, for example, a second upper limit temperature (for example, 750 ° C.) in which the temperature of the reformer detected by the temperature detector 3 is higher than the second temperature. If it is above, it can be performed by determining that the temperature of the reformer cannot be maintained at the second temperature. Note that the second upper limit temperature is set to a temperature lower than the heat resistant temperature of the reformer 1.

  When the temperature of the reformer 1 can be controlled to the second temperature, the determination result of step S204 is Yes, and the operation is maintained while the control temperature of the reformer is maintained at the second temperature. The operation ends (END).

  When the temperature of the reformer 1 cannot be controlled to the second temperature, the determination result in Step S204 is No, the operation is stopped (Step S205), and the determination operation ends (End).

  In stopping the operation of the hydrogen generator 100, the operations of the raw material supplier (not shown) and the water supplier (not shown) are stopped, and the hydrogen generation operation in the reformer is stopped. Note that when the operation of the hydrogen generator 100 is stopped, the operations of the raw material supplier (not shown) and the water supplier (not shown) may be stopped, and the combustion in the combustor 2 may be stopped.

[Second Modification]
In the hydrogen generator of this modification, the controller 5 performs the hydrogen generation operation in the reformer when the oxygen concentration in the raw material is the third state having a relatively high oxygen concentration in the second state. Stop.

  With such a configuration, it is possible to reduce reformer malfunctions such as reformer failure or reformer degradation.

  In the hydrogen generator of this modification, you may comprise similarly to 1st Embodiment except the said structure.

  Next, the hydrogen generator of this modification will be described in detail.

  The hardware configuration of the hydrogen generator of this modification can be the same as that shown in FIG. Therefore, the same name and code | symbol are attached | subjected about the component which is common in the fuel cell system of this modification, and the hydrogen generator 100 of 1st Embodiment, and detailed description is abbreviate | omitted.

  FIG. 4 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the second modification of the first embodiment.

  Hereinafter, the operation method of the hydrogen generator according to the first modification of the present embodiment will be described with reference to FIG.

  The operations in steps 301 to 302 are the same as those in steps S101 to S102 in FIG.

  When the state of the oxygen concentration in the raw material is the second state, the determination result in step S301 is Yes, and the controller 5 determines that the oxygen concentration state is the third state based on the information received from the temperature detector 3. It is determined whether it is in a state (step S103). Here, the third state refers to a state in which the oxygen concentration in the raw material is relatively high in the second state. Alternatively, the third state is a state in which it is difficult for the oxygen concentration in the raw material to continue the hydrogen generation operation in the reformer. For example, if the hydrogen generation operation is continued, the excessive temperature increase associated with the oxidation reaction of hydrogen Is defined as a state that may exceed the heat resistance temperature of the reformer 1. For example, the third state refers to a state where the oxygen concentration in the raw material is greater than 40000 ppm.

  The determination can be made, for example, based on whether or not the temperature detected by the temperature detector 3 is equal to or higher than a predetermined third upper limit temperature. In this case, when the detected temperature is equal to or higher than the third upper limit temperature, it is determined to be in the third state, and when it is lower than the third upper limit temperature, it is determined not to be in the third state. The third upper limit temperature can be appropriately set in consideration of the heat resistant temperature of the reformer 1, and can be set to 760 ° C., for example.

  The determination about the state of the oxygen concentration in the raw material can be performed by other methods as in the first embodiment.

  Specifically, for example, the oxygen concentration in the raw material may be determined based on the change rate of the temperature detected by the temperature detector 3, or may be determined based on the value detected by the oxygen concentration detector, Judgment may be made based on the value detected by the ammonia concentration detector, or based on at least one of the magnitude of the detected temperature of the first detector for detecting the temperature of the hydrodesulfurizer and the rate of change of the detected temperature. Alternatively, it may be detected by a pressure detector that detects the supply pressure of the raw material.

  In particular, the determination as to whether the oxygen concentration in the raw material is in the third state may be performed as follows.

  For example, in the case of determining based on the temperature change speed of the temperature detector 3, when the temperature change speed is equal to or higher than the second upper limit speed (for example, 70 ° C./min) larger than the first upper limit speed, It is determined that the oxygen concentration is in the third state.

  When the first detector for detecting the temperature of the hydrodesulfurizer is used as the oxygen concentration detector, the raw material is determined based on whether the detected temperature of the first detector is equal to or higher than the fifth upper limit temperature (for example, 350 ° C.). You may determine the state of oxygen concentration in it. Or you may determine the state of the oxygen concentration in a raw material based on whether the temperature change of the detected temperature of a 1st detector is more than a 4th upper limit speed | rate (for example, 40 degreeC / min).

  When an oxygen concentration detector is used as the oxygen concentration state detector, the state of oxygen concentration in the raw material is determined based on whether or not the detected concentration of the oxygen concentration detector is equal to or higher than the second upper limit oxygen concentration (for example, 40000 ppm). You may judge.

  When an ammonia concentration detector is used as the oxygen concentration state detector, the state of oxygen concentration in the raw material is determined based on whether or not the detected concentration of the ammonia concentration detector is equal to or higher than the second upper limit ammonia concentration (for example, 320,000 ppm). May be.

  When a pressure detector is used as the oxygen concentration state detector, oxygen in the raw material is determined based on whether the detected concentration of the pressure detector is equal to or lower than a second upper limit pressure value (for example, +0.2 kPa with respect to atmospheric pressure). The density state may be determined.

  When the oxygen concentration in the raw material is not in the third state, the determination result in step S303 is No, and the controller 5 changes the control temperature of the reformer 1 to the second temperature and operates the hydrogen generator 100. (Step S304), and the determination operation ends (END). Since the operation in step S304 is the same as that in step S103 in FIG. 3, detailed description thereof is omitted.

  If the determination result in step S303 is Yes, the operation is stopped (step S305), and the process ends (end). In stopping the operation, the operations of the raw material supplier (not shown) and the water supplier (not shown) are stopped, and the hydrogen generation operation in the reformer is stopped.

  Note that the present modification can be modified in the same manner as the first modification. Specifically, for example, the aspect of stopping the operation of the hydrogen generator 100 may be stopped as in the first modification.

(Second Embodiment)
The hydrogen generator according to the second embodiment includes a reformer that reforms a raw material to generate a hydrogen-containing gas, a combustor that heats the reformer, and a first oxygen concentration in the raw material that is relatively low. A controller that lowers the flow rate of the raw material supplied to the reformer when compared with the first state when the second state is relatively higher than the first state.

  The hydrogen generator according to the second embodiment is the hydrogen generator according to the first embodiment and the modification thereof, and the controller is configured to supply the flow rate of the raw material supplied to the reformer when in the second state. May be lowered as compared with the first state.

  The operation method of the hydrogen generator according to the second embodiment includes a step of reforming a raw material in a reformer to generate a hydrogen-containing gas, a step of heating the reformer by a combustor, and oxygen in the raw material Reducing the flow rate of the raw material supplied to the reformer when the second state is relatively higher than the first state where the concentration is relatively lower than when the first state is present. .

  The operation method of the hydrogen generator according to the second embodiment is the operation method of the hydrogen generator according to the first embodiment and the modification thereof, and is supplied to the reformer when in the second state. You may provide the step which reduces raw material flow volume rather than the time of being in a 1st state.

  In such a configuration, by reducing the raw material flow rate, the amount of hydrogen generated in the reformer is reduced, and the amount of heat generated by the reaction between hydrogen and oxygen is reduced. That is, it is possible to reduce the possibility that the operation will be stopped due to the excessive temperature rise in a state where the oxygen concentration in the raw material is high.

  In the hydrogen generator, the controller sets the control temperature of the reformer to the first temperature when in the first state, and the temperature of the reformer is equal to the first temperature when in the second state. The raw material flow rate supplied to the reformer may be reduced so as to be.

  In the hydrogen generation apparatus, the controller may lower the target raw material flow rate determined with respect to the target hydrogen generation amount of the reformer when it is in the second state than when it is in the first state. .

  In the hydrogen generator, when the controller cannot control the reformer temperature to the first temperature even when the raw material flow rate is decreased, the controller sets the reformer control temperature to the second temperature higher than the first temperature. It may be changed.

  With such a configuration, the possibility of being overheated and judged to be overheated in a state where the oxygen concentration in the raw material is high is reduced as compared with the case where the control temperature is not increased.

  “The case where the temperature of the reformer cannot be controlled to the first temperature” means, for example, a case where the temperature of the reformer is equal to or higher than the second upper limit temperature higher than the first temperature.

  In the hydrogen generator, the controller may stop the operation after changing the control temperature of the reformer to the second temperature and when the temperature of the reformer cannot be controlled to the second temperature.

  “Stopping the operation” means stopping the hydrogen generation operation in the reformer. Also, the stop of the hydrogen generation operation means that at least one of the operations necessary for the progress of the reforming reaction is stopped in the reformer. For example, it means stopping at least one of the supply of reaction raw materials to the reformer and the heating operation of the reformer. In the case of the steam reforming reaction, the reaction raw materials are the raw material and water vapor. In the case of the autothermal reaction, the reaction raw material is the raw material, water vapor and air. In the case of the partial oxidation reaction, the reaction raw material is the raw material and air. .

  The apparatus configuration of the fuel cell system according to this embodiment can be the same as that of the first embodiment. Therefore, the same reference numerals and names are assigned to common components, and detailed description thereof is omitted.

  FIG. 5 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the second embodiment. Hereinafter, an example of the above operation of the hydrogen generator will be described with reference to FIG. The operation is executed under the control of the controller 5. This also applies to other modified examples and embodiments.

  In the following, an operation method unique to the present embodiment will be described. However, such an operation method may be executed in combination with the operation method of the first embodiment and its modifications.

  When the hydrogen generator starts an operation for determining the oxygen concentration state (start), the controller 5 determines whether the oxygen concentration state is the second state based on the information received from the temperature detector 3. (Step S401). Here, the first state is when the oxygen concentration in the raw material is in a relatively low state. The second state refers to a state in which the oxygen concentration in the raw material is relatively higher than in the first state. The first state and the second state are appropriately set according to the design of the reformer. For example, the first state is set as a state in which it is in the range of 0 ppm to 1000 ppm, and the second state is The oxygen concentration in the raw material is set to be greater than 1000 ppm.

  The determination can be made, for example, based on whether or not the temperature detected by the temperature detector 3 is equal to or higher than a predetermined first upper limit temperature. In this case, when the detected temperature is equal to or higher than the first upper limit temperature, it is determined that the second state is established. When the detected temperature is lower than the first upper limit temperature, the second state is not established, that is, the first state is established. It is determined. The first upper limit temperature is defined as the temperature when the oxygen concentration in the raw material is in the second state, and a value smaller than the heat resistant temperature of the reformer 1 is set. For example, the first upper limit temperature can be 700 ° C.

  When the state of the oxygen concentration in the raw material is the first state, the determination result in step S401 is No, and the controller 5 maintains the raw material flow rate supplied to the reformer 1 without decreasing (step). S402), the determination operation ends (end).

  When the state of the oxygen concentration in the raw material is the second state, the determination result in step S401 is Yes, and the controller 5 decreases the flow rate of the raw material supplied to the reformer 1 (step S403). End the operation (END).

  Such an operation can reduce the possibility of the operation being stopped due to the excessive temperature rise determined in the second state where the oxygen concentration in the raw material is relatively high.

  In step S401, the determination method of whether or not the oxygen concentration in the raw material is in the second state higher than the first state is any method as long as the state of the oxygen concentration in the raw material can be determined. There may be. Specific details can be the same as step S101 of the first embodiment, and thus detailed description thereof is omitted.

  As a method of reducing the raw material flow rate supplied to the reformer 1 in step S403, for example, the target raw material flow rate determined for the target hydrogen production amount of the reformer 1 in the second state is set. This is done by making it smaller than in the first state.

  Specifically, for example, a correspondence relationship between a target hydrogen generation amount and a target flow rate (target raw material flow rate) of a raw material supplied to the reformer 1 with respect to the target hydrogen generation amount is summarized in a storage unit (not shown). Stored in table data. Further, the table data includes first table data used in the first state and second table data used in the second state, and the storage stores these. The target raw material flow rate with respect to the predetermined target hydrogen generation amount stored in the second table data is smaller than the target raw material flow rate with respect to the predetermined target hydrogen generation amount stored in the first table data.

  Here, when the controller 5 determines that the oxygen concentration in the raw material is in the first state, the controller 5 refers to the first table data and determines the raw material supplied to the reformer 1 with respect to the target hydrogen production amount. Determine the target flow rate (target raw material flow rate). On the other hand, when the controller 5 determines that the oxygen concentration in the raw material is in the second state, the controller 5 refers to the second table data and targets the raw material supplied to the reformer 1 with respect to the target hydrogen production amount. Determine the flow rate.

  The target raw material flow rate determination method is not limited to the above example. For example, in the hydrogen generator, when the storage unit stores either the first or second table data, and the oxygen concentration in the raw material does not correspond to the table data held by the storage unit The predetermined correction factor may be determined by multiplying the target raw material flow rate. Specifically, for example, when the storage unit holds only the first table data and the controller 5 determines that the second state is established, the target raw material flow rate of the first table data is set to this value. It is determined by multiplying by a correction rate (for example, 0.95) that reduces Alternatively, when the storage unit stores only the second table data and the oxygen concentration in the raw material is determined to be in the first state, the storage unit increases this to the target raw material flow rate of the second table data. It is determined by multiplying by a correction factor (for example, 0.95).

  The hydrogen generator does not hold the table data, but holds a program for executing a calculation process for calculating the target raw material flow rate from the target hydrogen generation amount in the storage unit, and executes the program to obtain the target raw material flow rate. You may calculate. At this time, for the target raw material flow rates in different states, for example, by multiplying the target raw material flow rate in a predetermined state (for example, the first state) by a correction factor, the other state (for example, the second state) A target raw material flow rate is determined.

  The target hydrogen generation amount may be the target hydrogen generation amount itself or an amount correlated with the target hydrogen generation (for example, target water supply amount, target power generation amount in the case of a fuel cell system).

[First Modification]
In the hydrogen generator of the present modification, the controller 5 sets the control temperature of the reformer 1 to the first temperature when in the first state, and the reformer 1 when the controller 5 is in the second state. The raw material flow rate supplied to the reformer 1 is lowered so that the temperature becomes the first temperature.

  The hydrogen generator of this modification may be configured in the same manner as in the second embodiment except for the above features.

  Next, the hydrogen generator of this modification will be described in detail.

  Since the hardware configuration of the hydrogen generator of this modification can be the same as that of the first embodiment, the same reference numerals and names are assigned to the respective components, and detailed description thereof is omitted.

  FIG. 6 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the first modification of the second embodiment.

  Hereinafter, the operation method of the hydrogen generator according to the first modification of the present embodiment will be described with reference to FIG.

  The operation in step S501 is the same as that in step S401 in FIG.

  When the state of the oxygen concentration in the raw material is the first state, the determination result in step S501 is No, and the controller 5 maintains and improves the flow rate of the raw material supplied to the reformer 1 without reducing it. The temperature of the mass device 1 is controlled to the first temperature (step S502), and the determination operation is ended (END). The control is performed by controlling the combustion amount of the combustor 2 as in the first embodiment.

  The first temperature can be 670 ° C., for example.

  When the state of the oxygen concentration in the raw material is the second state, the determination result in step S501 is Yes, and the controller 5 supplies the reformer 1 to the first temperature so that the temperature of the reformer 1 becomes the first temperature. The raw material flow rate is reduced (step S503), and the determination operation is ended (END). In order to control the temperature of the reformer 1 to the first temperature, the controller 5 not only reduces the flow rate of the raw material supplied to the reformer 1 but also burns the combustor 2 as in the first embodiment. The amount is also controlled.

[Second Modification]
In the hydrogen generator of the present modification, when the controller 5 cannot control the temperature of the reformer 1 to the first temperature even when the flow rate of the raw material is reduced, the control temperature of the reformer 1 is controlled from the first temperature. Also change to a higher second temperature.

  The hydrogen generator of this modification may be configured in the same manner as at least one of the hydrogen generators of the second embodiment and the first modification, except for the above characteristics. Next, details of the hydrogen generator of this modification will be described.

  Since the hardware configuration of the hydrogen generator of this modification can be the same as that of the first embodiment, the same reference numerals and names are assigned to the respective components, and detailed description thereof is omitted.

  FIG. 7 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the second modification of the second embodiment.

  Hereinafter, the operation method of the hydrogen generator according to the first modification of the present embodiment will be described with reference to FIG.

  The operations in steps S601 to 603 are the same as those in steps S501 to S503 in FIG.

  In this modified example, after step S603, it is determined whether or not the temperature of the reformer 1 can be maintained at the first temperature, that is, whether or not control is possible at the first temperature (step S604). The determination as to whether or not the temperature of the reformer 1 can be maintained at the first temperature is, for example, a second upper limit temperature (for example, 710) in which the temperature of the reformer 1 detected by the temperature detector 3 is higher than the first temperature. When the temperature is higher than or equal to (° C.), the temperature of the reformer 1 can be determined to be not maintained at the first temperature. Note that the second upper limit temperature is set to a temperature lower than the heat resistant temperature of the reformer 1.

  When the temperature of the reformer 1 can be controlled at the first temperature, the determination result in step S604 is Yes, and the operation is continued as it is.

  If the temperature of the reformer 1 cannot be controlled at the first temperature, the determination result of step S604 is No, and the control temperature of the reformer 1 is changed to a second temperature higher than the first temperature (step S605). . That is, the controller 5 controls the amount of the combustor 2 so that the temperature of the reformer 1 becomes the second temperature. The second temperature is set to a temperature lower than the heat resistant temperature of the reformer 1. The second temperature can be 730 ° C., for example. After changing the control temperature of the reformer to the second temperature, the determination operation ends (end).

[Third Modification]
In the hydrogen generator of the present modification, the controller 5 generates hydrogen in the reformer when the temperature of the reformer 1 cannot be controlled to the second temperature after changing the control temperature of the reformer 1 to the second temperature. Stop operation.

  With such a configuration, it is possible to reduce problems with the reformer such as a reformer failure or deterioration of the reformer.

  The hydrogen generator of this modification may be configured in the same manner as the hydrogen generator of at least one of the second embodiment, the first modification, and the second modification, except for the above features.

  Next, details of the hydrogen generator of this modification will be described.

  Since the hardware configuration of the hydrogen generator of this modification can be the same as that of the first embodiment, the same reference numerals and names are assigned to the respective components, and detailed description thereof is omitted.

  FIG. 8 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the third modification of the second embodiment.

  Hereinafter, the operation method of the hydrogen generator according to the third modification of the present embodiment will be described with reference to FIG.

  The operations in steps S701 to S705 are the same as those in steps S601 to S605 in FIG.

  In this modified example, after step S705, it is determined whether or not the temperature of the reformer 1 can be maintained at the second temperature, that is, whether or not control is possible at the second temperature (step S706). Whether or not the temperature of the reformer 1 can be maintained at the second temperature is determined by, for example, a third upper limit temperature (for example, 750) in which the temperature of the reformer 1 detected by the temperature detector 3 is higher than the second temperature. When the temperature is equal to or higher than (° C.), it can be performed by determining that the temperature of the reformer 1 cannot be maintained at the second temperature. Note that the second upper limit temperature is set to a temperature lower than the heat resistant temperature of the reformer 1.

  When the temperature of the reformer 1 can be controlled at the second temperature, the determination result of step S706 is Yes, the operation is maintained while the control temperature of the reformer 1 is maintained at the second temperature, and the determination operation is performed. End (end).

  If the temperature of the reformer 1 cannot be controlled at the second temperature, the determination result in step S706 is No, the operation is stopped (step S707), and the determination operation ends (end).

  In stopping the operation of the hydrogen generator, the operations of the raw material supplier (not shown) and the water supplier (not shown) are stopped, and the hydrogen generation operation in the reformer is stopped. Note that when the operation of the hydrogen generator is stopped, the combustion of the combustor 2 may be stopped in addition to the operation of the raw material supplier (not shown) and the water supplier (not shown). .

(Third embodiment)
The fuel cell system according to the present embodiment includes a hydrogen generator and any one of the hydrogen generators according to the first embodiment, the modifications of the first embodiment, the second embodiment, and the modifications of the second embodiment, and the hydrogen generator. And a fuel cell that generates electricity using the hydrogen-containing gas supplied from the fuel cell.

  With such a configuration, it is possible to reduce the possibility of the operation being stopped due to the excessive temperature rise in a state where the oxygen concentration in the raw material is high as compared with the conventional case.

  FIG. 9 is a block diagram illustrating an example of a schematic configuration of a fuel cell system according to the third embodiment. The fuel cell system 200 according to the third embodiment includes a fuel cell 20 in addition to the hydrogen generator 100.

  In the fuel cell system of this embodiment, the configuration other than the above is configured in the same manner as the hydrogen generator of the first embodiment, the modified example of the first embodiment, the second embodiment, and the modified example of the second embodiment. Can do. 9 and 1 are denoted by the same reference numerals and names, and description thereof is omitted.

  The fuel cell 20 generates power using the hydrogen-containing gas supplied from the hydrogen generator 100. The fuel cell 20 corresponds to the hydrogen utilization device in the first embodiment. For example, the fuel cell 20 generates power by using a hydrogen-containing gas as a fuel gas and separately supplied air as an oxidant gas. The fuel cell 20 may include a heat recovery mechanism that recovers heat that is simultaneously generated during power generation.

  The fuel cell 20 may be any type of fuel cell, such as a polymer electrolyte fuel cell (PEFC), a solid oxide fuel cell, or a phosphoric acid fuel cell.

  In the present embodiment, the operation of the fuel cell system 200 when the oxygen concentration in the raw material is relatively high can be the same as that of at least one of the first embodiment and its modification. Therefore, detailed description is omitted.

  In the fuel cell system 200 of the present embodiment, the operation of the hydrogen generator 100 is stopped and the power generation in the fuel cell 20 may be stopped in step S205 in the first modification of the first embodiment. . That is, the operation of the fuel cell system 200 may be stopped.

  Alternatively, in the fuel cell system 200 of the present embodiment, the operation of the hydrogen generator 100 may be stopped and the power generation in the fuel cell 20 may also be stopped in step S305 in the second modification of the first embodiment. . That is, the operation of the fuel cell system 200 may be stopped.

  In the fuel cell system 200 of the present embodiment, the operation of the hydrogen generator may be stopped and the power generation in the fuel cell 20 may be stopped in step S707 in the third modification of the second embodiment. That is, the operation of the fuel cell system 200 may be stopped.

  From the foregoing description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

  The hydrogen generator, the fuel cell system, and the operation method thereof according to the present invention provide hydrogen generation that can reduce the possibility that the reformer is judged to be overheated and shut down when the oxygen concentration in the raw material is high than before. It is useful as a device, a fuel cell system, and an operation method thereof.

DESCRIPTION OF SYMBOLS 1 Reformer 2 Combustor 3 Temperature detector 5 Controller 10 Raw material supply path 11 Hydrogen supply path 20 Fuel cell 100 Hydrogen generator 200 Fuel cell system

Claims (11)

A reformer that generates a hydrogen-containing gas by reforming the raw material;
A combustor for heating the reformer;
When the oxygen concentration in the raw material is in the first state that is relatively low, the control temperature of the reformer is set to the first temperature,
A controller that changes the control temperature of the reformer to a second temperature higher than the first temperature when the oxygen concentration in the raw material is in a second state that is relatively higher than the first state; A hydrogen generator comprising:   2. The hydrogen generation according to claim 1, wherein the controller stops operation when the temperature of the reformer cannot be controlled to the second temperature after changing the control temperature of the reformer to the second temperature. apparatus.   2. The hydrogen generator according to claim 1, wherein the controller stops the operation when the oxygen concentration in the raw material is a third state having a relatively high oxygen concentration in the second state. A reformer that generates a hydrogen-containing gas by reforming the raw material;
A combustor for heating the reformer;
When the oxygen concentration in the raw material is in the second state, which is relatively higher than the first state, the raw material flow rate supplied to the reformer is higher than in the first state. And a controller for lowering the hydrogen generator.   When the controller is in the first state, the control temperature of the reformer is the first temperature, and when the controller is in the second state, the temperature of the reformer is the first temperature. The hydrogen generator of Claim 4 which reduces the raw material flow volume supplied to the said reformer so that it may become.   The said controller makes the target raw material flow rate defined with respect to the target hydrogen production amount of the said reformer lower than it is in the said 1st state when it is in the said 2nd state. Hydrogen generator.   The controller changes the control temperature of the reformer to a second temperature higher than the first temperature when the temperature of the reformer cannot be controlled to the first temperature even if the flow rate of the raw material is decreased. The hydrogen generator according to claim 5.   The hydrogen generator according to claim 7, wherein the controller stops operation when the control temperature of the reformer cannot be controlled to the second temperature after changing the control temperature of the reformer to the second temperature. .   A fuel cell system comprising: the hydrogen generator according to claim 1; and a fuel cell that generates electric power using a hydrogen-containing gas supplied from the hydrogen generator. Generating a hydrogen-containing gas by reforming a raw material in a reformer;
Heating the reformer with a combustor;
When the oxygen concentration in the raw material is in a first state that is relatively low, the control temperature of the reformer is set to the first temperature;
Changing the control temperature of the reformer to a second temperature higher than the first temperature when the oxygen concentration in the raw material is in a second state relatively higher than the first state; A method for operating a hydrogen generator. Generating a hydrogen-containing gas by reforming a raw material in a reformer;
Heating the reformer with a combustor;
When the oxygen concentration in the raw material is in the second state, which is relatively higher than the first state, the raw material flow rate supplied to the reformer is higher than in the first state. and a step of reducing, operating method of the hydrogen generator.

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